As many as 90 million Americans could be ignoring their medical problems because they're scared of going to the doctor for simple screening tests. Dr. Oz says these people are letting their emotions put their lives at risk. "There are so many things we can do today that can prevent all the hardships down the road," he says. "People don't realize how important it can be for them."

One of those people who was hesitant to go is Nate, a Chicago firefighter. In October 2007, when Dr. Oz and 300 men took over The Oprah Show , Nate told Dr. Oz he was scared about colon cancer because his brother died at 35the same age Nate is now. Dr. Oz made Nate promise to get a colonoscopy, a colon cancer test.